This invention generally relates to a headrest. More particularly, the present invention pertains to a head rest device for a vehicle seat.
A known headrest device for a vehicle is disclosed in Japanese Patent Application Laid-Open Publication No. Hei 9 (1997)-382. This headrest device is supported on a seat back frame of a vehicle seat assembly and includes a head rest stay member and a frame member. The frame member of the headrest device is rotatably supported on a horizontal bar of the stay member at a connection portion of the frame member located at the lower portion of the frame member. The connection portion of the stay member engages the frame member with a friction force. In addition, a pad member is formed integrally with the frame and stay members, and covers the frame and an upper portion of the stay member.
To ensure a stable frictional engagement of the frame member on the stay ember, clamp members forming separately prepared parts of the frame are used for rotationally supporting the frame member on the stay member.
In the case of a headrest unit which has a frame directly connected with a stay member, it is difficult to control the friction force for the headrest substantially within a desirable range upon assembling the headrest device. To try to avoid large friction force changes or variations during assembly, it may be possible to employ well-prepared clamp members. However, this undesirably increases the number of parts as well as the cost of the headrest.
A need thus exists for an improved headrest device that is able to provide a relatively stable frictional force between the stay member and the frame member without significantly increasing the number of parts of the headrest device and without substantially increasing the cost associated with the headrest device.
According to one aspect of the invention, a headrest device includes a stay member and a frame member. The stay member has a pair of vertical supporting bars adapted to be supported on a seat back of a vehicle seat and a horizontal supporting bar connecting the pair of vertical supporting bars. The frame member has a connecting portion rotatably mounting the frame member on the horizontal supporting bar to produce a rotational friction force between the connecting portion and the horizontal supporting bar allowing the frame member to be fixed at a desired position relative to the stay member while also allowing the frame member to be rotated relative to the horizontal supporting bar upon application of a force. The frame member is provided with a slit having an intermediate portion and end portions, with the end portions of the slit extending towards the connecting portion so that the portion of the frame member bounded by the slit is resiliently deformed in a peripheral direction of the horizontal supporting bar to work as a fulcrum point for adjusting the rotational friction force between the connecting portion and the horizontal supporting bar.
According to another aspect of the invention, a headrest device includes a stay member, a frame member and a pad mounted on the frame member. The stay member has a pair of vertical supporting bars adapted to be supported on a seat back of a vehicle seat and a horizontal supporting bar connecting the pair of vertical supporting bars. The frame member includes first and second surface portions and a connecting portion positioned between the first and second surface portions, with the first and second surface portions overlapping one another and the connecting portion being mounted on the horizontal supporting bar in a frictionally engaging manner allowing the frame member to be rotated relative to the horizontal supporting bar while also allowing the frame member to be fixed at a desired position by the frictional engagement between the connecting portion and the horizontal supporting bar. One of the first and second surface portions is provided with a cantilevered portion that permits adjustment of an amount of the frictional engagement between the connecting portion and the horizontal supporting bar.
According to a further aspect of the present invention, a headrest device includes a stay member and a frame member. The stay member has a pair of vertical supporting bars adapted to be supported on a seat back of a vehicle seat and a horizontal supporting bar connecting the pair of vertical supporting bars. The frame member has a connecting portion rotatably mounting the frame member on the horizontal supporting bar to produce a rotational friction force between the connecting portion and the horizontal supporting bar allowing the frame member to be fixed at a desired position relative to the stay member while also allowing the frame member to be rotated relative to the horizontal supporting bar upon application of a force. The frame member is provided with at least one projection in contacting engagement with the horizontal supporting bar along a longitudinal direction of the horizontal supporting bar.
In accordance with another aspect of the invention, a headrest device includes a stay member, a frame member and a pad mounted on the frame member. The stay member has a pair of vertical supporting bars adapted to be supported on a seat back of a vehicle seat and a horizontal supporting bar connecting the pair of vertical supporting bars. The frame member includes first and second surface portions and a connecting portion positioned between the first and second surface portions. The first and second surface portions overlap one another with the connecting portion being at least partially wrapped around the horizontal supporting bar in a frictionally engaging manner allowing the frame member to be rotated relative to the horizontal supporting bar while also allowing the frame member to be fixed at a desired position by the frictional engagement between the connecting portion and the horizontal supporting bar. One of the first and second surface portions is provided with an upstanding projection positioned adjacent the connecting portion to facilitate positioning of the connecting portion relative to the horizontal supporting bar.